Flareless rigid tube end fitting



June 9, 1953 R. R. LA MARRE 2,641,437

FLARELESS RIGID TUBE END FITTING Filed July 13, 1949 32 3O 2O 22 I6 26 ROGER R- LAMARRE A 7'TOPNEYS Patented June 9, 1953 FLARELESS RIGID TUBE END FITTING Roger B. La Marre, Jackson, Mich, assignor to Aeroquip Corporation, Jackson, Mich, a corporation of Michigan Application July 13, 1949,Serial No. 104,410

1 Claim.

This invention relates to fiareless rigid tube end fittings of the type which employ a deformable sleeve member adapted to fit over the end of the tube which it is desired to couple to a relatively fixed adapter or other structure, such upon the adapter or like structure.

The problem in such type of fitting is the maintaining of sufficient grip upon the tube end without the introduction of an excessive over-lap between the tube end and the adapter or other structure to which it is desired to couple and afiix the rigid tubing. This problem is further complicated by the fact that in order to keep the overall dimensions of the end fitting as small as is practicable it is necessary that the grip upon the tube should be confined as close as possible to the end thereof to be coupled.

It is the object of the present invention to meet the above problems with the provision of a rigid flareless tube end fitting in which the amount of overlap is reduced to a minimum yet with the maintaining of an efficient grip upon the tube end. In carrying out the invention, the deformable sleeve member is formed to have abutting engagement at one end thereof with the tube end in opposition to the pressure applied to the sleeve member by the encirclin coupling member to deform the latter on to the tube end, and the sleeve member is formed bitingly to engage the tube towards the end of the sleeve member remote from its said abutting end, the said pressure being applied to the sleeve members at a point corresponding to the thus axially spaced point of biting engagement.

Another object of the invention is to provide a fitting of the above described type in which the deformable sleeve is of such improved construction that it cannot be improperly located in position but due to its inherent construction can only be located in the position in which it is intended to operate. This results from the fact that the sleeve has an inturned flange at one end which is adapted to have abutting contact with one end of the rigid tube and which precludes the sleeve from being slid onto the tube from its flanged end.

These and other objects and advantages of the invention will become apparent from a consideration of the following description and claim with reference to the accompanying drawings in which:

Fig. I is a half longitudinal section of one embodiment of the invention, with the end fitting parts positioned ready for deformation of the tube end clamping sleeve, and

Fig. II is a similar view of Fig. I with parts in operative position, the clampin sleeve being shown deformed and bitingly engaged in the tube end.

Referring to the drawings It indicates a substantially rigid fiareless tube and I2 a deformable sleeve which is adapted to be slid over one end of the tube and to be deformed, by the action of tightening a union nut 14, to cause an annular knife edge I6 to bite into the tube surface as indicated at l8 in Figure II.

The sleeve [2 has its knife edge 16 defined towards one end of the sleeve, being the end remote from an inturned flange 20 which is adapted to abutagainst the end edge of the tube 10 corresponding to that on the end portion of the tube to which the end fitting is required to be applied. This flange defines an interior cylindrical surface portion 22 which has sliding engagement with the tube end and is axially spaced from the annular knife edge [6, the latter in turn being axially spaced from the opposite end edge 24 of the sleeve by the existence of the concave interior surface portion 26, the latter being preferably such as defines the end edge 24 on a larger diameter than the knife edge l6.

On its exterior surface the sleeve I2 is rounded, as shown, and presents a sealing contact zone 28 to the tapered surface 30 of a nipple 32 or an adapter or other structure to which it is desired releasably to connect the tube in.

The union nut M has screw-threaded engagement with the nipple 32, as shown, and is also formed with an interior tapered surface 34, the angle of which is approximately 20 to 30 to the horizontal and by which surface the required pressure is applied to the sleeve l2 in the neighborhood of the knife edge I6 to deform the sleeve and cause the knife edge to bite into the tube surface.

Preferably, the union nut I4 is formed with a tapered elongated extension 36 to give the maximum support to the tube I0, but the nut may take other shapes and forms, one of which is shown dotted in Figure I.

V To apply the fitting the sleeve [2 is slipped over the end of the tube ID to abut the end flange 20 against the tube end as shown in Figure 1. The existence of this flange precludes the possibility of the sleeve being slid on from the wrongvend and insures that the knife edge I 6 is properly positioned for biting into the tube when the union nut I 4 is tightened. This applies pressure to the sleeve in the region of the tapered nut surface 34, which pressure has a component along the tube end which is opposed by the abutting end flange 20 and the stop ofiere'd by the nipple 32, and results not only in the tube end being adequately supported against collapse but also! leaves the knife edge IE to be bitingly engaged in the tube as the sleeve is deformed. with the continued tightening action of the union nut l4 and with the use of the mechanical advantageresulting from a screw-threading action.

As more clearly shown in Fig. II, the end edge 24 is deformed into contiguous relation Withthe outer wall of the tube 10 with the result that the tube 10 is supported on both sides out the portion engaged by the knife edge It, namely, by the portion 22 and theend edge it Also as: seen in Fig. II, the curvature of the wall of the concaved portion 26 assuresthe localization of pressure at the knife edge l6.

Having thus described the invention in one of the adaptor, as'ealingsleeve for the tube having an abutment end and an axially spaced deformable end, said sleevehaving: prior to deformation an internal: diameter throughout the portion of its length which will receive with a sliding fit one :end of-a tube with theiminor portion of said sleeveatsaidabutment end being in the form of an inturned flange with which the tube end abuts, the abutment end of said sleeve being of substantially greater cross-sectional area than that of said deformable end to present a rigid relatively undeformable sealing and abutment portion radially spaced from said inturned flange and engaging with the conical portion of the adaptor" only at a point adjabent the threaded engagement between the adaptor and the nut, the outer surface of said sleeve bulging outward adjacent said abutment end and then having a generally inward tapering surface toward said deformable end to terminate in a. tapered nose portiomthe interiortof said sleeve being concaved on opposite sides of an intermediate point adjacent the tapered nose portion of said sleeve to provide an annular interior and deformable knife edge and to reduce the cross-sectional area of the tapered portion of said sleeve at the deformable end, the outer tapered surface of said sleeve opposite said knife edge being slightly curved at the point of initial engagement with the'coni-calsurface of the nut whereby said curved surfaceis deformable and: said knife edge is contractableupon the tube with the terminal portionof said tapered nose contiguous with the tubes References Cited in: the file of this patent UNITED" STATES PATENTS 

